the only two reason im not boosting this new motor is because i would need to purchase a forged crank and my CR is too high.

right now im running stock trickflow 23 degree heads with 64cc chambers, eagle hbeams, weisco 10.5-10.6:1 slugs and a scat cast crank. would 76cc heads drop me low enough to run approx 8lbs???

im going to get my block splayed and a forged crank to handle the power but i dont know if it would be best to get new pistons to drop the CR or if i should get another set of heads (if that would drop me low enough).

any suggestions?

 

I ran my L98 mildly barely modified (airfoil and msd coil) with a P1SC intercooled 5-8psi for a year and a half. The CR was around 9.5-9.75:1 stock.

 

Yeah, i would think you'd be ok with the 76's.

 

LT1 are what 10.5:1 and get away with 6psi

so Id say with 76cc heads and at least a alky/water injection kit you should be fine.

 

Is this on a 305 or a 350? Is your true current compression at 10.5 now? Reason I ask is that 64cc heads on a 305 you are probably less than 10.5 now (since 305 pistons assume a 58cc head). Just trying to nail down exactly where we're starting from.

 

You could also buy some multi layered steel head gaskets to drop if further.

 

no i forgot to say in my first post this is a 383 im building so i dont know the exact compression but it will be around 10.5:1, the 305 is actually coming out this weekend

 

Give a list of parts that you want to use. Amount of boost, intercooled? Alky-inj.? We're shooting in the dark w/ nothing go on but 383 and 76cc heads.

 

well in the first post i listed the approx compression, what heads im using, the amount of boost i would like to run and yes it will be intercooled (TT setup single intercooler). alky injection is a possiblilty but wasnt leaning towards it

 

It's looking like 10:1 static compression w/ the numbers that I was using. Assuming that there has been no machine work done to the block on a .03 overbore.

You can get away w/ it, but it'll require a good tune.

 

your cam makes a differance as well. what are you using?

 

Do you already have some of the parts? You say you havent built it yet. So if you dont have parts yet why not just get some low comp. pistons for the get go.?

 

cam is 230/236 .510/.520

the reason i ask is because the 383 im building now has good weisco slugs in it and i basically wanted to turn this motor into a turbo motor in a year or so. it was either get new pistons or heads and swwapping heads for one is much easier when the motor is in and two, i wanted to get a better flowing set of heads than the trickflows anyway

 

If you have flattop pistons in a 383 with a set of 76cc heads you could have compression as low as 9.1:1 and as high as 9.7:1, depending on piston deck height, gasket thickness and how many cc's worth of "dish" there is in the piston valve reliefs.

.025" deck height + 9cc Fel Pro .039" head gasket + 7cc of piston valve reliefs = 9.1 compression

.000" deck height + 9cc Fel Pro .039" head gasket + 5cc of piston valve reliefs = 9.7 compression